Method for performing pulse chromium plating based on trivalent chromium in sulfate system

Abstract

The invention discloses a high-efficiency environment-friendly pulse plating metallurgy method for performing thick chromium plating based on trivalent chromium in a sulfate system. The method is characterized by comprising the following steps: dissolving rare earth oxides in an acid, so as to obtain a rare-earth salt solution; dissolving chromium sulfate salt, aluminum sulfate, boric acid, a complexing agent and methanol with water, and adding the rare-earth salt solution, so as to obtain a chromium sulfate salt-aluminum sulfate-boric acid-complexing agent-methanol-rare-earth salt plating solution; electroplating a to-be-plated plating piece into the electroplating solution; controlling the electroplating process conditions as follows: the distance between a pulse electroplating power supply and a plating tank is 2-3m, a wire refers to a multi-stranded core wire, and an anode refers to a Cu-matrix coating electrode plate; the current density of a connecting wire is 28-90A / dm<2> and needs to be far higher than the average current, the pH value of the electroplating solution is 2-4, the temperature refers to 25-60 DEG C, the stirring speed is 100-600rpm, the plating time refers to 30-90 minutes, the pulse frequency refers to 100-500Hz, and the duty ratio is 5-100 percent; and washing the plating piece subjected to complete electroplating, and airing. The method disclosed by the invention has the advantages of coating flatness and compactness, good adhesiveness, high current efficiency, high environmental friendliness and the like.

Description

[0001] Technical field [0001] The present invention relates to the technical field of electrochemistry, in particular to a kind of pulse electroplating efficient environment-friendly metallurgical method based on sulfate system trivalent chromium plating thick chromium. Background technique [0002] Traditional process of DC electroplating: During DC electroplating, the metal ions plated out in the plating solution are gradually consumed in the solution near the cathode surface, resulting in a difference in the concentration of the metal ions to be plated and the ions in the solution. This difference increases as the current density used increases. When the concentration of this ion in the liquid layer near the cathode drops to 0, the so-called limiting current density is reached, and the mass transfer process is completely controlled by diffusion. [0003] Contents of the invention [0004] (1) Technical problems to be solved [0005] The technical problem to be solved by...

AI Technical Summary

Problems solved by technology

[0002] Traditional process DC electroplating: During DC electroplating, the metal ions plated out in the plating solution are gradually consumed in the solution near the cathode surface, resulting in a difference in the concentration of the metal ion to be plated and the ion in the solution

This difference increases with the current density used